The present invention relates to intervertebral disc replacement procedures and devices used in such a procedures. A purpose of the invention is to compress bone graft material within the disc space and also to prevent any bone graft material from migrating out of the disc space after an interbody fusion device is implanted therein. More particularly, the present invention includes an anchor screw inserted through a plate or plug and connected with an interbody fusion device.
In existing intervertebral disc replacement procedures, an opening or hole is created in the annulus fibrosis surrounding the disc space to create an access portal into the disc space for introduction of one or more devices after the disc space is initially cleared. After the introduction of the device(s), it is a common procedure to fill the remaining open area of the disc space with bone graft material to provide additional structure to the disc space and to promote bone growth between the adjacent vertebral bodies.
However, the hole created in the annulus typically remains partially or fully open after the procedure. In some instances, the hole can be closed in such a way that does not substantially prevent the movement and/or migration of the bone graft material from its implanted location. The closure of the annulus, even if sealed in a generally effective manner, may require some open space within the disc space adjacent the hole in the annulus in order to properly use certain instruments to complete the procedure. As a result, the implanted bone graft material is not sealed within the disc space and/or is not packed tightly enough into its implanted location. The bone graft material can then be subject to movement and even migration out of the disc space through the area of the annulus opened for initial access to the disc space.
In addition, any biologic material provided to the disc space during the procedure is subject to migration out through the hole in the annulus. This can potentially create a situation in which the biologic is located in areas outside of the repaired disc space that are not intended or even able to support bone growth.
Therefore, there is a need for a device that more securely closes the access hole created in the annulus during an intervertebral disc replacement procedure to ensure that the materials inserted into the disc space after that procedure remain firmly in place and do not migrate or shift to undesired degrees. Methods of using such devices and methods that more securely close and pack the disc space after an intervertebral disc replacement procedure are also needed.